Expansible fluid engine



w; LUNDQUIST EXPANSIBLE FLUID ENGINE Sept. 8, 1964 3 Sheets-Sheet 1 FiledAug. 1, 196:5

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FJXPANSIBLE FLUID ENGINE I Filed Aug. 1 1 963 3 Sheets-Sheet 2 INVENTOR Marc/v G. lu/voau/sr 66 60 66 $4M MMM 0m %%Mm Array/Vera p 8, 1964' a. LUNDQUIST 3,147,669

' EXPANSIBLE FLUID ENGINE V FiledAug. 1, 1963 s Sheets-Sheet s ATTOP/YEYS United States Patent M 3,147,669 EXPANSBLE FLUID ENGINE Wilton G. Lundtguist, 32 Hollis Drive, Ho-Hodfus, NJ. Filed Aug. 1, E63, Ser. No. 299,328 6 Claims. or, 91-134 This invention relates to expansible fluid engines of the uniflow type.

Uniflow engines utilizing steam as the expansible fluid have been known since 1872 wherein steam was admitted into the cylinder between the cylinder head and the outer end of the piston and exhausted through ports controlled by the outer end of the piston. This invention relates. to improvements in this general type of engine and is not limited to the use of steam as a working fluid but contemplates the use of any suitable expansible fluid, preferably a high pressure fluid.

An object of the invention is to provide improved valving mechanism for controlling the intake of Working fluid.

Another object of the invention is to provide an engine of simple and rugged construction, adapted to be economically manufactured and having a very high H.P./wt. ratio.

In general, the present embodiment of this invention utilizes a plurality of cylinder blocks arranged in star formation about an axis of symmetry and preferably each cylinder block is provided with a pair of cylinder bores in which are positioned a pair of pistons. A common cylinder head is utilized and is in communication with the pair of cylinder bores. However, it is to be understood that in its broader aspects the invention is equally applicable where each cylinder block is provided with only one cylinder. A balanced inlet valve is disposed in each cylinder block between the pair of cylinder bores and serves to control the admission of working fluid into the pair of cylinders. As more particularly described in my Patent No. 2,989,022, all of the pistons are pivotally secured to the outer ends of connecting rods whose inner ends are pivotally secured to a true motion frame which is mounted so as to revolve in an orbital path whose radius is equal to the throw of a crankshaft while held against rotation about its own axis. A cam track is integrally formed on said true motion frame so as to follow the orbital path of said frame and comprises a plurality of spaced apart cam track segments, one for each cylinder block. A valve tappet is slidably mounted in each cylinder block in alignment with the inlet valve and carries a roller in register with a corresponding cam track segment, so that the valve is opened by the motion imparted by the cam track segment; the valve being biased to closed position by a spring. Due to the orbital movement of the relatively short track segments, each segment is moving essentially tangential to its cooperating roller at the moment of roller pick-up contact and at the moment of roller lift-off relative to the cam track segment. This is an important feature since it permits the pick-up and seating of the tappet to be controllably gentle regardless of engine speed.

Further specific features and advantages of the invention will be hereinafter more fully set forth with reference.

to the annexed drawings, showing a presently preferred embodiment of the invention, in which:

FIG. 1 is a side elevational view of an embodirnent of the present invention, partly in longitudinal section;

FIG. 2 is an end elevational view of the engine of FIG. 1, partly in section, to show certain structural details;

FIG. 3 is an enlarged sectional view; FIG. 3A is a cross-sectional view taken on line Zia-3a of FIG. 3;

FIG. 4 is a cross-sectional view taken on line 4-4. of FIG. 3, showing further details of the back pressure valve;

3,147,659 Patented Sept. 8, 1964 FIG. 4A is a plan view showing a detail of FIG. 4; and

FIG. 5 is a cross-sectional View taken on line 55 of FIG. 2 showing further details of the inlet ports.

Referring more particularly to FIGS. 1 and 2 of the drawings: The engine comprises two banks of cylinders designated in general as I and II, and each bank comprises four cylinder blocks. The cylinder blocks of bank I are designated in general as A, B, C and D (FIG. 2) and bank II comprises comparable cylinder blocks all mounted on a crankcase designated in general as 20. In order to identify parts relating to specific cylinder blocks, the reference numeral applicable to all cylinder blocks will be followed by the letter designating the particular cylinder block. Each cylinder block comprises a pair of cylinder bores such as 21 and 22 containing cooperating pistons such as 23 and 24 pivotally secured to the upper ends of connecting rods 25 and 26 respectively, whose lower ends are pivotally secured to a true motion frame 27 (FIGS. 1 and 2 and 3). The true motion frame rides on the crankpins 28 and 29 of two crankshafts 3t? and 31 respectively which are parallel to the axis of symmetry A.S. of the engine and are suitably journaled in the engine frame 26. The frame 27 links the crankshafts together so that they rotate in phase and any point on the frame describes a true circle whose radius is equal to the crank throw; hence the frame 27 revolves in an orbit but is restrained from rotating about its own axis.

Cam Operation Cam track means (FIGS. 2 and 3) is integrally formed with the true motion frame 27 and comprises cam track segments SeA, sea, 36C and 36D corresponding to the cylinder blocks A, B, C and D respectively. These segments alternate with grooves such as 35 within which the inner ends of the connecting rods such as 25 and 2d are seated. The segments have a thickness about equal to the width of the slots 35 (FIGS. 1 and 3A). Each of these segments is constructed and arranged in the manner now to be described with particular reference to the cam track segment 36A (FIG. 3). The zero lift line is designated as 37 and the full length of the cam segment extends from 38 to 39 and the operating portion of the cam track segment commences on the zero lift line at 40 which will be called the pick-up point where the cam commences to open the valve and the point of maximum raise of the cam track segment is designated 41 from where the track gradually descends to the zero lift line 37 substantially at 39.

Inlet Valve The inlet valve is designated in general as 45 and is mounted in its respective cylinder block between the pistons such as 23 and 24 with its longitudinal axis of reciprocation parallel to the axes of said pistons. The valve member 45 comprises a stem 46 whose upper end is journaled in a bore provided in the cylinder block such as A and whose lower end slidably extends through a valve guide plate 47 which is held in fixed position between a shoulder 48 formed in the cylinder block and the upper end of an elongated sleeve 49 disposed in a bore in the cylinder block and is suitably held in position by a ring nut 50 which threadedly engages the cylinder block. The lower end of the valve stem 46 carries rigidly secured thereto a stop Washer 51 between which and the valve plate 47 a helical compression spring 52 is secured so as to constantly bias the valve 46 toward closed position. Beneath the lower end of the valve stem 46 is positioned a tappet 53 provided with a head 54 for engaging the lower end of the valve stem for lifting the same to open the valve. The tappet head 54 is limited in its downward movement by a cooperating shoulder 55 formed in the sleeve 49. A tappet roller 56 is pivotally mounted in the lower end of the tappet 53 and is disposed in slots such as 57 to maintain the roller 56 in registered alignment with the cam track segment 37. An axially extending passageway 53 passes through the valve stem 46 and tappet head 54 for the purpose of equalizing the fluid pressure in order to provide a balanced valve. Working fluid is admitted to the inlet valve through inlet cavities such as 59 and oil which, when the valve is open, communicate with the upper ends of the respective cylinders such as 21 and 22 by way of inlet throats 61 and 62. The valves such as 45' are provided with spaced apart valve heads such as 63 and 64 which slidably fit within the openings at and s2 respectively; so that when the valve is in closed position with the tappet tresting upon the shoulder 55 the valve heads are seated within the valve openings to prevent the flow of fluid from the cavities 59 and 60 and when the valve is moved to open position, as shown in FIG. 3, the working fluid is permitted to pass through the valve openings 61 and 62 into the corresponding cylinder bores 21 and 22. Referring to FIG. 5, it will be seen that the working fluid is admitted into the cavities 59 and at on opposite sides of the cylinder block by means of inlet passages such as 65 and 66.

Each cam track segment such as 36 is in operable contact with its corresponding tappet roller for only approximately 90 of crankshaft rotation and for the remainder of the time the tappet assembly rests on the shoulder 55. The crankshafts 3tl31 and frame 27 advance 45 from the point 33 on the cam track segment and as the cam track segment continues to move in the direction of the arrow, the valve under the action of the cam has opened and continues to open and then close during the next 45 or 50 of crank motion. By selecting cam contouring, the crank angle of inlet valve cut-off can be selected to give a wide range of desirable cut-off points within the range of crank angle mentioned above. Referring to FIG. 2, it will be noted that a valve tappet 54B is resting on its corresponding seat 55B and the inlet valve 45B is closed. The cam track segment 36B is moved completely out of contact with its cooperating roller 56B and will remain out of contact until the frame 27 brings the corresponding segment such as 3613 around to the proper pick-up point on the next cycle.

Working Fluid Exhaust Each cylinder bore (FIGS. 2 and 3) is provided with a plurality of exhaust ports such as 70 which pass through the corresponding cylinder walls and are arranged in a circumferential series about the cylinder bores. These exhaust passages lead into an exhaust manifold such as 71 which in the present embodiment discharge into the crankcase from which the gasses are vented to atmosphere. The exhaust passages such as 70 are uncovered as the tops of the pistons such as 23 and 24 move downwardly to the end of their stroke.

Back Pressure Relief Valves In certain instances, it may be desirable to avoid high back pressure created at the upper end of the return stroke of the pistons and in order to relieve such back pressure the following relief valve mechanism may be employed. Referring more particularly to FIGS. 3 and 4, the head of each piston such as 23 and 24 is provided with a valve seat such as 72 which is in communication with the interior of the piston such as 23 by means of a plurality of passages such as 74 (FIG. 3). The valve seat 72 is adapted to receive a mushroom type valve head 76 carried on a valve stem '77 guidingly disposed in bore 77. The stem 77 is provided with a pair of downwardly extending spaced apart tines such as 78 which straddle the end 79 of the corresponding connecting rod such as 25 and serve to hold the needle bearing washer retainers such as 8th in position. The tines 73 are provided with elongated slots such as 81 to provide clearance for a wrist pin such as 82 and which serve also to guide the valve.

.4 The upper end of the connecting rod is provided with a cam such as 83 which serves to raise the valve 76 to open position against the bias of a torsion spring such as 84 (FIG. 4a), the free end of which passes through an opening in one of the tines such as 78 and the body of which is seated in a groove such as 85 provided within the skirt of the piston and is locked in position by a split ring washer such as 86. It will be seen from the foregoing that as each piston starts its return stroke the corresponding cam such as 83 raises the valve head 76 from its cooperating seat such as 72 and permits the pressure fluid to flow through the cavity 73 and the passageways 74 into the piston from which it is vented to atmospheric pressure by way of the crankcase. Then, at or near the top of the return stroke the valve is closed by the spring.

The above structural recitations with respect to bank I and related parts also applied to bank II. Referring to FIG. 1, in the present embodiment the crankshafts such as 30 and 31 are drivingly connected to a common output power shaft 87, the output end of which is suitably journaled in a housing 88 as by means of a combined radial and end thrust ball bearing 90. The housing 88 is suitably secured to the engine crankcase as at M. The common drive shaft 87 is provided at its inner end with an internal gear 92 which is drivingly connected with crankshafts such as 3th and 31, such driving connection being suitably made as by means of pinion gears such as 93, one of which is carried on each crankshaft and in mesh with cooperating idle gears (not shown) disposed therebetween and in mesh with the internal gear 92.

Having thus described my invention with particularity with reference to the preferred embodiment of the same, and having referred to some of the possible modifications thereof, it will be obvious to those skilled in the art, after understanding my invention, that other changes and modifications may be made therein without departing from the spirit and scope of the invention and I aim in the appended claims to cover such changes and modifications as are within the scope of the invention.

What I claim is:

1. In an expansible fluid engine of the unifiow type, the combination of a plurality of cylinder blocks symmetrically disposed about a common axis, each cylinder block having a cylinder bore With a piston operably disposed therein and a working fluid inlet valve for controllably admitting working fluid to the cylinder bore, the cylinder bore walls being provided with exhaust ports controlled by said pistons, a crankshaft with its axis parallel to the axis of symmetry, a true motion frame carried by the crankpin journal of the crankshaft, means for causing the true motion frame to travel in an orbit whose radius is equal to the throw of said crankshaft, means for preventing substantial rotation of said true motion frame during orbital travel, connecting rods pivotally attached to the pistons and the true motion frame, a cam track integral with the true motion frame and moving therewith in orbit, a tappet roller mounted and guided in each cylinder block and controlling the inlet valve of its corresponding cylinder by the motion imparted to the inlet valve by the roller motion as it follows the convolutions of the cam track.

2. An expansible fluid engine as set forth in claim 1 in which said cam track comprises relatively short angularly spaced apart cam track segements each cooperating with its corresponding cam follower, the orbital movement of said cam track segments being such that at the moment of roller pick-up contact and at the moment of roller lift-off from the cam track the cam segment is moving substantially tangential to the tappet roller and thereby pick-up and seating of the tappet is gentle regardless of the engine speed.

3. An expansible fluid engine as set forth in claim 1 in which at least two crankshafts of equal crank throw are employed and the true motion frame is carried jointly by the crankpin journals of said crankshafts to thereby cause the true motion frame to travel in an orbit whose radius is equal to the throw of said crankshafts and to prevent substantial rotation of said true motion frame during orbital travel.

4. An expansible fluid engine as set forth in claim 1 in which each piston is provided with a back-pressure relief valve and means for opening said valves at any desired predetermined pressure.

5. An expansible fluid engine as set forth in claim 4 in which each back-pressure valve is a poppet valve seated in a valve opening provided in the center of the piston head and communicating with the inner end of the cylinder through openings provided in the piston head and is held in axial alignment by a pair of downwardly extending tines in straddling engagement with the connecting rod, the tines being provided with elongated openings through which the wrist pin extends, the valve being urged to closed position by a torsion spring anchored within the piston skirt and a cam provided at the upper end of the connecting rod for opening the valve near the lower end of the return stroke and closing it near the upper end of the return stroke of the piston.

6. In an expansible fluid engine of the uniflow type, the combination of a plurality of cylinders symmetrically disposed about a common axis, each cylinder having a cylinder bore with a piston operably disposed therein and a working fluid inlet valve for controllably admitting working fluid to the cylinder bore, the cylinder bore walls being provided with exhaust ports controlled by said pistons, a crankshaft with its axis parallel to the axis of symmetry, a true motion frame carried by the crankpin journal of the crankshaft, means for causing the true motion frame to travel in an orbit whose radius is equal to the throw of said crankshaft, means for preventing substantial rotation of said true motion frame during orbital travel, connecting rod pivotally attached to the pistons and the true motion frame, a cam track integral with the true motion frame and moving therewith in orbit, a tappet roller mounted and guided adjacent each cylinder and controlling the inlet valve of its corresponding cylinder by the motion imparted to the inlet valve by the roller motion as it follows the convolutions of the cam track.

References Cited in the file of this patent UNITED STATES PATENTS 1,045,630 Stumpf Nov. 26, 1912 2,475,458 Orshansky July 5, 1949 2,989,022 Lundquist June 20, 1961 UNITED STATES-"PATENT" OFFICE CERTIFICATE OF CORRECTION Patent No. 3,147,669 September 8, 1964 Wilton G Lundquist It iShreby eertified. that error appears in the above numbered patent requ'iringcorrection and that the said Letters Patent should read as corrected" below Column 3, line 69, for "bore 77" read bore 77 column 4, line 17, for "applied" read applies column 6. line 12, for "rod" read rods Signed and sealed this 5th day of January 1965.

Altest:

E'RNEs wr swIDER' e d EDWARD J. BRENNER Aitfesting Officer Commissioner of Patents 

1. IN AN EXPANSIBLE FLUID ENGINE OF THE UNIFLOW TYPE, THE COMBINATION OF A PLURALITY OF CYLINDER BLOCKS SYMMETRICALLY DISPOSED ABOUT A COMMON AXIS, EACH CYLINDER BLOCK HAVING A CYLINDER BORE WITH A PISTON OPERABLY DISPOSED THEREIN AND A WORKING FLUID INLET VALVE FOR CONTROLLABLY ADMITTING WORKING FLUID TO THE CYLINDER BORE, THE CYLINDER BORE WALLS BEING PROVIDED WITH EXHAUST PORTS CONTROLLED BY SAID PISTONS, A CRANKSHAFT WITH ITS AXIS PARALLEL TO THE AXIS OF SYMMETRY, A TRUE MOTION FRAME CARRIED BY THE CRANKPIN JOURNAL OF THE CRANKSHAFT, MEANS FOR CAUSING THE TRUE MOTION FRAME TO TRAVEL IN AN ORBIT WHOSE RADIUS IS EQUAL TO THE THROW OF SAID CRANKSHAFT, MEANS FOR PREVENTING SUBSTANTIAL ROTATION OF SAID TRUE MOTION FRAME DURING ORBITAL TRAVEL, CONNECTING RODS PIVOTALLY ATTACHED TO THE PISTONS AND THE TRUE MOTION FRAME, A CAM TRACK INTEGRAL WITH THE TRUE MOTION FRAME AND MOVING THEREWITH IN ORBIT, A TAPPET ROLLER MOUNTED AND GUIDED IN EACH CYLINDER BLOCK AND CONTROLLING THE INLET VALVE OF ITS CORRESPONDING CYLINDER BY THE MOTION IMPARTED TO THE INLET VALVE BY THE ROLLER MOTION AS IT FOLLOWS THE CONVOLUTIONS OF THE CAM TRACK. 